Change Over Time

Landsat Thematic Mapper (TM) data have been collected for almost 20 years (Since 1982) and provide an incredible archive for detecting changes in a region over time. This protocol shows how to overlay TM images and determine gain or loss of different land cover types. The tutorial (Change.pdf) describes the process and also deals with interpreting what is seen in the image, and why the image colors are produced. To do the tutorial, you will need to download two images of Durham, NH, used in the tutorial. They are contained in the file Images.

For further investigation, two images of Nashville, TN, are available to practice with. These are contained in the "Nash.sit" file for Macintosh computers, and the "" file for PC machines.

Download the Change.pdf tutorial (839 k)

Download Macintosh images: Images.sit (194 k), Nash.sit (1.8 MB)

Download PC images: (258 k), (2.2 MB)

Nashville 1992, Nashville 1999, Change Detection

Changes in Nashville, TN from 1992 to 1999